Internal combustion engine structure



March 28, 1933. D s u 1,903,160

INTERNAL COMBUSTION ENGINE STRUCTURE Filed May 13, 1932 Snngntor flans'e y [Ashe/e2,

Patented Mar. 28, 1933 PATENT OFFICE DORSEY F. ASBURY, OF BECOMES ISLAND, MARYLAND INTERNAL COMBUSTION ENGINE STRUCTURE 7 Application filed May 13,

My invention relates to an internal combustion engine/Which includes an exhaust port having entrance and discharge ends, the former of which'is controlled by a poppet valve, and has for its purpose the provision of means on the valve head for shielding from the gas current only that side of a length of the valve stem which is remote from the discharge end of the port and which would otherwiserbe directly exposed to such current in the port.

A further purpose of my invention is to provide means assuring assembly of the valve head in such angular position about its axis as will dispose the stem shielding means carried thereby on that side of the exposed length of the valve stem which is remote from the discharge end of the port.

When the exhaust valve of my invention is 0 open the shield carried thereby has the major portion thereof disposed in the combustion chamber of the engine and operates to obstruct the nearest straight and therefore highest velocity path of exhaust products discharging from the combustion chamber, so that the side of the valve stem remote from the discharge end of the exhaust port will be heated no hotter than the side of the stem nearest said port discharge end and thus cause uniform expansion throughout the stem and consequent central and level seating of the valve head at all times. This central seating of the valve head under service conditions, due to non-warping of the valve stem, for the reasons previously stated, permits the use of a very low angle valve seat, so that the diameter of the valve port and the lift of the valve may be decreased perceptibly and still have more opening affording communication between the valve port and combustion chamber when the valve is lifted after deducting the amount of opening obstructed by the shield on the valve head.

In the drawing chosen to illustrate my invention the scope whereof is set forth in the appended claims:

Figure 1 is a vertical section of a cylinder head casting showing my invention incorpo- 59 rated the poppet valve shown being in open 1932. Serial No. 611,199.

position with respect to the. exhaust port which it controls;

Figure 2, a section on the line 22 of Figure 1; V

Figure 8, a section on the line 3-3 of Figure 1;

Figure 4, a section on the line 44 of Figure 1; and

Figure 5, a fragmental perspective view of the exhaust port valve showing the stem shield which is carried by the valve head.

Referring to the drawing A indicates the cylinder head casting of a water cooled internal combustion engine, said casting being shaped to provide the combustion chamber 10 of an engine cylinder and to also provide an exhaust port 11 into and through which exhaust products are discharged from the chamber 10. The entrance end of the port 11 is controlled by an exhaust poppet valve B which includes a head 12 and stem 13, said stem being slidable in a bearing 14 mounted in the casting A and having a portion between the bearing and valve head exposed to exhaust products in the port 11. This bearing 14 is extended on the outsideof the casting A and isprovided with a longitudinally extending recess 15 opening through its outer end for a purpose that will presently appear. A coil valve spring 16 surrounds the outer half of the bearing 14 and reacts from the outer face of the casting A against'the valve stem 13 to normally maintain the valve head 12 engaged upon its seat 12. The outer or movable end of the spring 16 is engaged in a pocket formed in the valve stem in the manner described and claimed in my prior Patent 1,789,209,,January 13, 1931', such engagement of the spring with the valve stem being effected through the recess 15 in the bearing 14 and constituting a means for assuring the assembly of the valve in a given angular position about its axis. This means for controlling the assembled position of the valve serves an important purpose in my present invention and such purpose will be presently revealed.

Formed on the inner face of the valve head 12'is a shield 17 which, when the valve is assembled, is disposed in shielding relation to only that side of the Valve stem 13 which is remote from the discharge end of the port 11. The assembly of the valve to so dispose said shield is controlled and assured by the necessity of engaging the spring 16 with the valve stem through the bearing recess 15. The valve B is adapted to be lifted to open position, as shown in Figure 1, by an oscillating rocker arm 18. In the absence of the shield 17 the highest velocity path of exhaust products in passing from the combustion chamber into the port 11 would be through the space occupied by the shield and as the rate of imparting heat to a surface by hot combustion products varies as the velocity of the products against the surface and does not vary with the size of the opening through which the products of combustion travel and as the valve stem is located in the middle of such path of high velocity direct impingement of exhaust gases against the valve stem will occur with the result that the side of the valve stem remote from the discharge end of the port would be heated to a higher temperature than the side of the stem nearest said discharge end of the port and there would occur a greater amount of expansion on the hottest side of the stem with resulting warping thereof and faulty seating of the valve head with respect to its seat. My shield 17 obstructs this path of high velocity and thereby prevents direct impingement of the exhaust gases against the shielded side of the stem and thus oppositely disposed sides of the stem will be heated symmetrically so that the stem will expand straight longitudinally and maintain the valve head central and level with its mating seat 12.

I claim:

1. In a gas engine structure, a cylinder including a gas port having entrance and discharge ends, a poppet valve controlling the entrance end of the port, said valve including a head and a stem with the latter having a length thereof exposed to gas current in the port, and means on the valve head shielding from the gas current only that side of the exposed length of the stem which is remote from the discharge end of the port.

2. In a gas engine structure, a cylinder including a gas port having entrance and discharge ends, a poppet valve controlling the entrance end of the port, said valve including a head and a stem with the latter having a length thereof exposed to gas current in the port, and a formation on the inner face of the valve head shielding from the gas current only that side of the exposed length of the stem which is remote from the discharge end of the port.

3. In a gas engine structure, a cylinder including a gas port having entrance and discharge ends, a poppet valve controlling the entrance end of the port, said valve in cluding a head and a stem with the latter having a length thereof exposed to gas current in the port, a formation on the inner face of the valve head and on one side only there of with respect to the valve stem, and means preventing the assembly of the valve in any angular position about its axis other than that which will dispose said formation in position to shield from the gas current only that side of the exposed length of the valve stem which is remote from the discharge end of the port.

4. In a gas engine structure, a cylinder including a gas port having entrance and discharge ends, a poppet valve controlling the entrance end of the port, said valve including a head and a stem with the latter having a length thereof exposed to gas current in the port, a formation on the inner face of the valve head and on one side only thereof with respect to the valve stem and means preventing the assembly of the valve in any angular position about its axis other than that which will dispose said formation in position to shield from the gas current only that side of the exposed length of the valve stem which is remote from the discharge end of the port, said means comprising a guide bearing for the valve stem having a lateral opening and a valve spring having one end engaged through said opening and in a pocket formed in the valve stem.

DORSEY F. ASBURY. 

